Memory allocation wrappers backed by libttak. More...

#include <stddef.h>
#include <ttak/mem/owner.h>
#include <cwist/core/mem/arena.h>

Include dependency graph for alloc.h:

Classes
struct	cwist_scratch_t
	Backing state for cwist_scratch_alloc()/CWIST_SCRATCH_DEFER: a single block-scoped allocation that prefers a recycled arena generation and falls back to cwist_alloc() when the request doesn't fit one (see cwist/core/mem/arena.h – only CWIST_ARENA_DEFAULT_GENERATION_BYTES-sized generations hit the zero-libttak-GC recycle path, so cwist_scratch_alloc() always requests the default size and never a custom one). More...

Macros
#define	CWIST_ATTRIBUTE_CLEANUP(func)
	Variable cleanup attribute for GCC/Clang; no-op on other compilers (e.g. TinyCC), where the variable then needs an explicit cwist_free() like today.

#define	CWIST_DEFER_FREE CWIST_ATTRIBUTE_CLEANUP(cwist_defer_free_cb)
	Attach to a pointer variable's declaration to cwist_free() it automatically when that variable's enclosing block scope exits, on every return path (GCC/Clang; no-op on TinyCC).

#define	cwist_alloc_scoped(var, cast, size)
	Declare `var` as a `cast` -typed pointer to a fresh cwist_alloc() block that is freed automatically when the enclosing block exits. Equivalent to combining cwist_alloc() with CWIST_DEFER_FREE, spelled as one declaration.

#define	CWIST_SCRATCH_DEFER CWIST_ATTRIBUTE_CLEANUP(cwist_scratch_cleanup)
	Attach to a cwist_scratch_t variable's declaration so its allocation (arena- or heap-backed, whichever cwist_scratch_alloc() picked) is released automatically when the enclosing block exits.

Functions
ttak_owner_t *	cwist_create_owner (void)
	Lazily create (or return) the shared CWIST owner context.

void *	cwist_malloc (size_t size)
	Allocate zeroed memory via the CWIST owner context.

void *	cwist_alloc (size_t size)
	Allocate zeroed memory tracked by libttak.

void *	cwist_alloc_array (size_t count, size_t elem_size)
	Allocate zeroed memory for count elements.

void *	cwist_realloc (void *ptr, size_t new_size)
	Resize an existing allocation (libttak tracked).

char *	cwist_strdup (const char *src)
	Duplicate a string using libttak-backed storage.

char *	cwist_strndup (const char *src, size_t n)
	Duplicate up to n bytes of a string (libttak-backed).

void	cwist_free (void *ptr)
	Free memory obtained via cwist_alloc/cwist_strdup/etc.

Detailed Description

Memory allocation wrappers backed by libttak.

Definition in file alloc.h.

Macro Definition Documentation

◆ cwist_alloc_scoped

#define cwist_alloc_scoped	(	var,
		cast,
		size
	)

Value:

void *_cwist_scoped_##var CWIST_DEFER_FREE = cwist_alloc(size); \

cast var = (cast)_cwist_scoped_##var

CWIST_DEFER_FREE

#define CWIST_DEFER_FREE

Attach to a pointer variable's declaration to cwist_free() it automatically when that variable's encl...

Definition alloc.h:101

cwist_alloc

void * cwist_alloc(size_t size)

Allocate zeroed memory tracked by libttak.

Definition alloc.c:17

cap

size_t cap

Definition otel.c:56

Declare var as a cast -typed pointer to a fresh cwist_alloc() block that is freed automatically when the enclosing block exits. Equivalent to combining cwist_alloc() with CWIST_DEFER_FREE, spelled as one declaration.

cwist_alloc_scoped(name, char *, 64);
snprintf(name, 64, "...");
// name is cwist_free()'d automatically here

Definition at line 116 of file alloc.h.

◆ CWIST_ATTRIBUTE_CLEANUP

#define CWIST_ATTRIBUTE_CLEANUP ( func )

Variable cleanup attribute for GCC/Clang; no-op on other compilers (e.g. TinyCC), where the variable then needs an explicit cwist_free() like today.

Mirrors TTAK_ATTRIBUTE_CLEANUP in lib/libttak/include/ttak/types/ttak_compiler.h.

Definition at line 64 of file alloc.h.

◆ CWIST_DEFER_FREE

#define CWIST_DEFER_FREE CWIST_ATTRIBUTE_CLEANUP(cwist_defer_free_cb)

Attach to a pointer variable's declaration to cwist_free() it automatically when that variable's enclosing block scope exits, on every return path (GCC/Clang; no-op on TinyCC).

Usage:

void *buf CWIST_DEFER_FREE = cwist_alloc(256);
if (something) return; // buf is freed here too
...
// and freed here, at the end of the block it was declared in

Only safe for a pointer that does not outlive the block it is declared in (i.e. never stored into a struct field, global, or queued job argument that another function/thread/job will read later). A pointer that does escape must not use this – see cwist_gc_scope_track() / cwist_gc_scope_disown() in cwist/core/mem/gc.h instead, which handle lifetimes that cross those boundaries.

Definition at line 101 of file alloc.h.

◆ CWIST_SCRATCH_DEFER

#define CWIST_SCRATCH_DEFER CWIST_ATTRIBUTE_CLEANUP(cwist_scratch_cleanup)

Attach to a cwist_scratch_t variable's declaration so its allocation (arena- or heap-backed, whichever cwist_scratch_alloc() picked) is released automatically when the enclosing block exits.

cwist_scratch_t buf_s CWIST_SCRATCH_DEFER = {0};
unsigned char *buf = cwist_scratch_alloc(&buf_s, needed);
if (!buf) return -1;
...
// buf_s's backing storage is released here, on every return path